Inflatable seat belts have included perforated fabrics (U.S. Pat. No. 3,801,156). Other seat belts have included folded woven fabric bodies within a rupturable cover (U.S. Pat. Nos. 5,346,250 and 5,383,713). Inflatable seat belts have also been pleated and stitched for use prior to inflation (U.S. Pat. No. 3,866,940).
Prior inflatable seat belts have included decorative covers that had little or no load bearing ability. Further, the attachment between the inflatable sections and the non-inflatable sections lacked sufficient reinforcement to withstand the high loading occurring during a crash.
Broadly, the preferred embodiment of the present invention comprises a vehicle seat and seat belt system including a two-part torso belt section with an inflatable inner component inserted into and coextensive with an outer component. The outer component comprises a tubular webbing made of fabric or other suitable material having strength characteristics similar to conventional seat belting. The tubular form of the outer component is formed by weaving two opposite edges of the webbing with a frangible seam that is designed to rupture when the inflatable inner component is inflated. However, even when the outer component seam is ruptured, the webbing still continues to act as a conventional seat belt. It remains attached at both ends in a manner similar to the manner in which conventional seat belts are attached.
The inflatable inner component comprises an inflatable tube, bladder or other inflatable component positioned co-extensively within the tubular webbing of the outer component. The frangible seam or knitted catch cord of the outer component allows the inner inflatable component, as it inflates, to exit the outer component through a rupture opening in the tubular webbing during the period of vehicle deceleration pending a crash. A dynamic crash event occurs when the vehicle is in motion when it encounters a crash or collision. A static crash event occurs when the vehicle is stationary when something else crashes into or collides with it.
The expansion pressure and forces of the inflation of the inner component cause the frangible seam of the tubular webbing of the outer component to rupture due to the shearing of the catch cord. The inner inflatable component, when inflated, also acts in a similar manner to the outer component, with both components acting in a manner similar to a conventional seat belt. That is to say that both the inflated inner inflatable component and the outer component are capable of bearing the tensile load impressed thereon by a passenger""s deceleration in a crash event.
The inner inflatable component, additionally, functionally acts as an air bag, to spread the load and cushion the passenger during that crash event. The combination of outer component and inner inflatable component may also be used in a lap belt section of a seat belt, as well as in the torso belt section.
The belt system may be used in combination with a structural seat having a frame in which a belt enclosure and anchor are positioned behind the occupant and secured to the seat frame. The enclosure houses the torso belt section of the system, which includes the outer and inner inflatable components. An inflator is positioned within the inner inflatable component. The amount of belting withdrawn from the enclosure depends on the size.-and/or shape of the occupant as he or she buckles up. Alternatively, the belt enclosure and anchor may be mounted on other portions of the vehicle including its frame.